The present invention relates to a process for the preparation of polymers containing Nxe2x86x92O terminal groups and to compositions comprising polymers obtained by this process.
The present invention relates to the preparation of polymers characterized by a low polydispersity range, preferably a polydispersity range which is lower than 3, and an enhanced monomer to polymer conversion efficiency. In particular, this invention relates to a stable, free radical initiated polymerization process by the ATRP (Atom Transfer Radical Polymerization) method which produces homopolymers, random copolymers, block copolymers, multiblock copolymers, graft copolymers and the like having a low polydispersity range and predetermined molecular weights.
Polymers or copolymers prepared by a conventional free radical polymerization reaction inherently have broad molecular weight distributions and a polydispersity range which is generally greater than three. This is explained by the fact that the half-life of most free radical initiators is relatively long, ranging from several minutes to hours. Polymeric chain reactions are initiated at different points of time which enables the initiators to generate growing chains of various lengths at any time period during the polymerization process. Moreover, the propagating chains may react with each other in free radical side reactions known as combination and disproportionation. Both are irreversible chain terminating reaction steps. The formation of chains of varying lengths is terminated at different points of time during the reaction, resulting in polymers of very different chain lengths, i.e. from very small to extremely long, and broad polydispersity ranges. Whenever a homogeneous molecular weight distribution is desirable in a free radical polymerization process, the growth of the polymer chains is to be initiated simultaneously to avoid termination at different points of time.
Therefore, any conventional free radical polymerization process is characterized by significant drawbacks, such as difficulties in predicting or controlling the molecular weight distribution of the polymer obtained and the polydispersity range. Furthermore, free radical polymerization processes are difficult to control. Most polymerization reactions are strongly exothermic, rendering it almost impossible to efficiently remove heat from the highly viscous polymer reaction mixture. The problems of conventional free radical polymerization reactions of the types mentioned above may also result in an undesirable formation of gel-type polymers of broad molecular weight distribution. They are difficult to handle in subsequent working-up steps, such as separation, purification, filtering and drying.
There is an urgent need for suitable agents which are useful for overcoming these drawbacks and which provide an efficient control of free radical initiated polymerizations. This will result in the preparation of polymers of defined chemical, and physical properties, such as viscosity, hardness, gel content, clarity, high gloss, durability and the like.
Therefore, the efficient control of reaction parameters in free radical polymerization processes is highly desirable. Among the different proposed methods some may be defined by the term xe2x80x9clivingxe2x80x9d polymerization. This method aims at a defined chain growth by the efficient reduction of chain terminating side reactions. Such a polymerization would provide for molecular weight control and narrow molecular weight distribution (MWD).
U.S. Pat. No. 4,581,429 discloses a free radical polymerization process which controls the controlled or xe2x80x9clivingxe2x80x9d growth of polymer chains to produce oligomeric homopolymers and copolymers, including block and graft copolymers. A process embodiment is the use of initiators of the partial formula Rxe2x80x2Rxe2x80x3Nxe2x80x94Oxe2x80x94X. In the polymerization process the free radical species Rxe2x80x2Rxe2x80x3Nxe2x80x94O. and .X are generated. .X is a free radical group, e.g. a tert.-butyl or cyanoisopropyl radical, capable of polymerizing monomer units containing ethylene groups. The monomer units A are substituted by the initiator fragments Rxe2x80x2Rxe2x80x3Nxe2x80x94O. and .X and polymerize to structures of the type: Rxe2x80x2Rxe2x80x3Nxe2x80x94Oxe2x80x94Anxe2x80x94X. Specific Rxe2x80x2Rxe2x80x3Nxe2x80x94Oxe2x80x94X initiators mentioned are derived from cyclic structures, such as 2,2,6,6-tetramethylpiperidine, or open chain molecules, such as di-tert.-butylamine.
WO 96/30421 discloses a controlled or xe2x80x9clivingxe2x80x9d polymerization process of ethylenically unsaturated polymers such as styrene or (meth)acrylates by employing the ATRP method. According to this method initiators are employed which generate a radical atom such as .Cl, in the presence of a redox system of transition metals of different oxidation states, e.g. Cu(I) and Cu(II), providing xe2x80x9clivingxe2x80x9d or controlled radical polymerization.
A general drawback of this prior art method is seen in the fact that the polymer chains prepared by ATRP contain halogen as terminal fragment which has been transferred from the polymerization initiator. The content of halogen is generally undesirable in polymers. Halogen, especially chlorine and bromine, is subject to the removal as hydrogen halide depending on temperature, especially above 150xc2x0 C. The double bond thus formed is subject to a reaction with atmospheric oxygen which decreases the antioxidative resistance of the polymer. Moreover, hydrogen halide liberated from the polymer reacts with other functional groups present in the polymer, such as ester groups present in acrylates. Depending on the type of the polymer, chlorine is also removed in the form of a radical which might initiate undesirable chain reactions in the polymer structure.
The removal of halogen from the polymer structure, especially the terminal position of the polymer chain, is the problem to which the present invention particularly relates. It is desirable to have the halogen replaced with suitable substituents.
M. Sawamoto and M. Kamigaito, J. Macromol. Sci. (J.M.S.)xe2x80x94Pure Appl. Chem. A 34(10, pp. 1803-1814 (1997) disclose ATRP of methyl acrylate with the initiator dichloroacetophenone and a catalyst system consisting of RuCl2(PPh3)3 and the co-catalyst Al(O-iPr)3. They report that the polymerization reaction is terminated with the addition of large amounts of TEMPO (=2,2,6,6-TEtraMethylPiperidyl-1-Oxide) or galvinoxyl. No products are reported to have been isolated and no properties have been disclosed.
It has surprisingly been found that terminal halogen in polymerisates, especially prepared by ATRP, is effectively replaced by the free radical species Rxe2x80x2Rxe2x80x3Nxe2x80x94O., which may have an open chain or cyclic structure.
The present invention relates to a process for the preparation of a polymer of the formula 
wherein:
In represents a polymerization initiator fragment of a polymerization initiator capable of initiating polymerization of monomers or oligopolymers containing ethylene groups;
p represents a numeral greater than zero and defines the number of initiator fragments;
A represents an oligopolymer or polymer fragment consisting of repeating units of polymerizable monomers or oligopolymers containing ethylene groups;
x represents a numeral greater than one and defines the number of repeating units in A;
B represents a monomer, oligopolymer or polymer fragment copolymerized with A;
y represents zero or a numeral greater than zero and defines the number of monomer, oligopolymer or polymer repeating units in B;
q represents a numeral greater than zero;
one of R1 and R2 represents C1-C7-alkyl and the other represents C0-C4-alkyl or C1-C4-alkyl substituted by C1-C4-alkoxycarbonyl or C1-C4-alkoxy; or
R1 and R2 together with the adjacent carbon atom both represent C3-C7-cycloalkyl;
R3 and R4 are as defined as R1 and R2;
Ra represents C1-C4-alkyl, cyano, C1-C4-alkoxycarbonyl, C1-C4-alkanoyloxy, C1-C4-alkanoyloxy-C1-C4-alkyl, carbamoyl, mono- or di-C1-C4-alkylcarbamoyl, mono- or di-2-hydroxyethylcarbamoyl, amidino, 2-imidazolyl, 1-hydroxy-2-hydroxymethyl-2-propylcarbamoyl, or 1,1-dihydroxymethyl-2-hydroxycarbamoyl; and
Rb is as defined as Ra; or
Ra and Rb together represent a divalent group and form a 5-, 6-, 7- or 8-membered aliphatic or aromatic heterocyclic group, which may contain 1-3 additional heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur;
with the proviso that compounds of the formula I, wherein R1, R2, R3 and R4 represents methyl and Ra and Rb represents 1,3-propylene is excluded; which comprises polymerizing by atom transfer radical polymerization (ATRP) an aliphatic monomer or oligomer containing ethylene groups in the presence of a polymerization initiator of the formula:
[In"Brketclosest"pXqxe2x80x83xe2x80x83(II),
wherein p and q are as defined above, In represents a radically transferable atom or group capable of initiating polymerization of monomers or oligopolymers containing ethylene groups and xe2x80x94X represents a leaving group; and replacing xe2x80x94X in a polymerisate of the formula
xe2x80x83(In"Parenclosest"p"Brketopenst"Axxe2x80x94By"Brketclosest"Xqxe2x80x83xe2x80x83(III),
wherein In, X, A, B, x, y, and p and q are as defined above, with a Nxe2x86x92O compound of the formula 
wherein R1-R4 and Ra and Rb are as defined above, in the presence of a catalytically effective amount of an oxidizable transition metal complex catalyst.
The polymers according to the present invention are useful for many applications including a variety of specific technical applications, such as block copolymers used as compatibilizers for polymer blends, or dispersants for coating systems. The polymers or copolymers are characterized by a homogeneous molecular weight distribution and low halogen content. They are especially useful for as oligomers or polymers in the coating technology, for the preparation of thermoplastic films, toner res ins and liquid immersion development ink resins or ink additives for electrographic imaging processes.
In a polymer (I) the group In represents the polymerization initiator fragment of a polymerization initiator (II), which is capable of initiating the polymerization of the fragments A and B and subsequently proceeds by a reaction mechanism known under the term ATRP. A suitable polymerization initiator contains a radically transferable atom or group .X and is described in WO 96/30421 and WO 98/01480. A preferred radically transferable atom or group .X is .Cl or .Br, which is cleaved as a radical from the initiator molecule and subsequently replaced after polymerization as a leaving group with a Nxe2x86x92O compound (IV). The index p is 1 if one group .X is present (q=1) in the polymerization initiator (II). The polymerization initiator may also contain more than one groups .X. In this case q may be 2 or 3.
A preferred embodiment of the invention relates to polymers, wherein p represents the numeral one; q represents a numeral from one to three; and In, A, B, x, y and R1-R10 are as defined above.
A preferred polymerization initiator (II) is selected from the group consisting of C1-C8-alkylhalides, C6-C15-aralkylhalides, C2-C8-haloalkyl esters, arene sulfonyl chlorides, haloalkanenitriles, xcex1-haloacrylates and halolactones.
Specific initiators are selected from the group consisting of xcex1,xcex1xe2x80x2-dichloro- or xcex1,xcex1xe2x80x2-di-bromoxylene, p-toluenesulfonylchloride (PTS), hexakis(xcex1-chloro- or xcex1-bromomethyl)-benzene, 2-chloro- or 2-bromopropionic acid, 2-chloro- or 2-bromoisobutyric acid, 1-phenethyl chloride or bromide, methyl or ethyl 2-chloro- or 2-bromopropionate, ethyl-2-bromo- or ethyl-2-chloroisobutyrate, chloro- or bromoacetonitrile, 2-chloro- or 2-bromopropionitrile, xcex1-bromo-benzacetonitrile and xcex1-bromo-xcex3-butyrolactone (=2-bromo-dihydro-2(3H)-furanone).
The term polymer comprises oligopolymers, cooligopolymers, polymers or copolymers, such as such as block, multi-block, star, gradient, random, comb, hyper-branched and dendritic copolymers as well as graft or copolymers. An oligopolymer A contains at least two repeating units of polymerizable aliphatic monomers containing ethylene groups.
The aliphatic monomer or oligomers may be water-soluble or water-insoluble and may contain one or more olefinic double bonds. The monomers may be of low (monomeric) or high (oligomeric) molecular mass. Examples of monomers containing one olefinic double bond are styrenes which may be substituted at the phenyl group by additional substituents selected from the group consisting of hydroxy, C1-C4-alkoxy, halogen, e.g. chloro, and C1-C4-alkyl, e.g. methyl, acrolein, acrylonitrile, acrylic or C1-C4-alkylacrylic acid-(C1-C4-alkyl)4ammonium salts, acrylic or C1-C4-alkylacrylic acid-(C1-C4-alkyl)3NH salts, acrylic or C1-C4-alkylacrylic acid-C1-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid hydroxy-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid-di-C1-C4-alkylamino-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylamides, N,N-di-C1-C4-alkyl substituted acrylic or C1-C4-alkylacrylamides, and acrylic or C1-C4-alkylacrylic acid anhydrides.
Specific examples of such monomers are styrene, 4-hydroxystyrene, xcex1-methylstyrene, p-methylstyrene, 4-chlorostyrene, methyl, ethyl, n-butyl, isobutyl, tert.-butyl, 2-ethylhexyl, isobornyl, glycidyl, 2-hydroxyethyl or 2-dimethylaminoethylacrylate or the corresponding methacrylates, acrylic or methacrylic acid amide, or acrylic or methacrylic acid-N,N-dimethyl or -diethyl amide. Silicone acrylates are also advantageous.
x represents a numeral greater than one and defines the number of repeating units in A. The lowest number is two. A preferred range of x is from 2 to 1000.
The above-mentioned aliphatic monomers may also be present in the polymer as comonomers B, or as oligopolymer or polymer fragments B copolymerized with A.
y represents zero or a numeral greater than zero and defines the number of monomer, oligopolymer or polymer repeating units in B. A preferred range of y is from 0 to 1000.
A preferred group of aliphatic monomers is selected from the group consisting of styrene, acrolein, acrylonitrile, acrylic or C1-C4-alkylacrylic acid-C1-C18-alkyl esters, acrylic or C1-C4-alkylacrylic acid hydroxy-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid-di-C1-C4-alkylamino-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylamides and acrylic or C1-C4-alkylacrylic acid anhydrides.
A particularly preferred group of aliphatic monomers is selected from the group consisting of styrene, acrylic or C1-C4-alkylacrylic acid-C1-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid hydroxy-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid di-C1-C4-alkylamino-C2-C4-alkyl esters, and acrylic or C1-C4-alkylacrylamides, e.g. styrene, methyl, ethyl, n-butyl, isobutyl, tert.-butyl, 2-ethylhexyl, isobornyl, glycidyl, 2-hydroxyethyl or 2-dimethylaminoethyl(meth)acrylate, or (meth)acrylic acid amide.
Examples of monomers containing two or more double bonds are diacrylates of ethylene glycol, propylene glycol, neopentyl glycol, hexamethylene glycol or of bisphenol A, 4,4xe2x80x2-bis(2-acryloyloxyethoxy)-diphenylpropane, trimethylolpropane triacrylate or tetraacrylate or vinyl acetate.
A polymerizable aliphatic monomer containing ethylene groups is characterized by a relatively high molecular mass from about 500 to 3000. Suitable examples are acrylisized epoxy resins or acrylisized polyesters. Unsaturated oligomers of this kind may also be referred to as prepolymers.
In a polymer (I) one of R1 and R2 represents C1-C7-alkyl, and the other represents C114 C4-alkyl or C1-C4-alkyl substituted by C1-C4-alkoxycarbonyl or C1-C4-alkoxy; or
R1 and R2 together with the adjacent carbon atom both represent C3-C7-cycloalkyl;
R3 and R4 are as defined as R1 and R2;
Ra represents C1-C4-alkyl, cyano, C1-C4-alkoxycarbonyl, C1-C4-alkanoyloxy, C1-C4-alkanoyloxy-C1-C4-alkyl, carbamoyl, mono- or di-C1-C4-alkylcarbamoyl, mono- or di-2-hydroxyethylcarbamoyl, amidino, 2-imidazolyl, 1-hydroxy-2-hydroxymethyl-2-propylcarbamoyl, or 1,1-dihydroxymethyl-2-hydroxycarbamoyl; and
Rb is as defined as Ra; or
Ra and Rb together represent a divalent group and form a 5-, 6-, 7- or 8-membered aliphatic or aromatic heterocyclic group, which may contain 1-3 additional heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur, e.g. a piperidine, piperazine, morpholine or imidazolidine group. The heterocyclic group may also be condensed with a phenyl group. If Ra and Rb together represent a divalent group, R1 and R2 and R3 and R4 together may also represent oxygen (exo-substitution) or R5 and R6 or R7 and R8 together or R5 and R6 and R7 and R8together represent oxygen.
In a polymer (I) the substituents R1, R2 and Ra and R3, R4 and Rb in a group of the partial formula 
together with the adjacent carbon atom on the nitrogen atom preferably represent groups of the partial formulae 
A preferred embodiment of the invention relates to the preparation of polymers (I), wherein one of R1 and R2 represents methyl and the other one represents methyl or ethyl and one of R3 and R4 represents methyl and the other one represents methyl or ethyl and Ra and Rb together represent a group of the formula 
wherein
R5, R6, R7 and R8 independently of one another represent hydrogen, methyl or ethyl; and
one of R9 and R10 independently of the other represents hydrogen or substituents or R9 and R10 both represent substituents.
A particularly preferred embodiment of the present invention relates to a process for the preparation of a polymer of the formula 
wherein:
In represents a polymerization initiator fragment of a polymerization initiator II capable of initiating polymerization of monomers or oligopolymers containing ethylene groups;
p represents a numeral greater than zero and defines the number of initiator fragments;
A represents an oligopolymer or polymer fragment consisting of repeating units of polymerizable monomers or oligopolymers containing ethylene groups;
x represents a numeral greater than one and defines the number of repeating units in A;
B represents a monomer, oligopolymer or polymer fragment copolymerized with A;
y represents zero or a numeral greater than zero and defines the number of monomer, oligopolymer or polymer repeating units in B;
q represents a numeral greater than zero;
R1, R2,R3 and R4 represent C1-C4-alkyl;
R5, R6, R7 and R8 represent hydrogen; and
one of R9 and R10 independently of the other represents hydrogen or substituents or R9 and R10 both represent substituents,
which comprises polymerizing by atom transfer radical polymerization (ATRP) an aliphatic monomer or oligomer containing ethylene groups in the presence of a polymerization initiator (II) having a radically transferable atom or group capable of initiating polymerization of monomers or oligopolymers containing ethylene groups and replacing the leaving group xe2x80x94X in a polymerisate (III) with a Nxe2x86x92O compound of the formula 
wherein R1-R10 are as defined above, in the presence of a catalytically effective amount of an oxidizable transition metal complex catalyst.
Another preferred embodiment of the present invention relates to the preparation of a polymer of the formula: 
wherein In, A, B, x, y, and R1-R10 are as defined above.
In the polymers (IA) and (IB) the cyclic Nxe2x86x92O containing terminal group represents a group of the partial formula 
wherein R1-R8 are as defined above and the 4-position is substituted by one or two substituents. Preferred groups B0 which contain substituents in 4-position are represented by the partial formulae 
wherein
R1-R6 are as defined above;
m represents a numeral from one to four;
n represents one, two or three;
if m represents one,
Ra represents hydrogen, C1-C18-alkyl which is uninterrupted or interrupted by one or more oxygen atoms, 2-cyanoethyl, benzoyl, glycidyl, or represents a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, of an a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms, where each carboxylic acid can be substituted in the aliphatic, cycloaliphatic or aromatic moiety by 1 to 3 xe2x80x94COOZ groups, in which Z represents H, C1-C20-alkyl, C3-C12-alkenyl, C5-C7-cycloalkyl, phenyl or benzyl; or
Ra represents a monovalent radical of a carbamic acid or phosphorus-containing acid or a monovalent silyl radical; or
if m represents 2,
Ra represents C2-C12-alkylene, C4-C12-alkenylene, xylylene, or represents a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms, of a cycloaliphatic or aromatic dicarboxylic acid having 8 to 14 carbon atoms or of an aliphatic, cycloaliphatic or aromatic dicarbamic acid having 8 to 14 carbon atoms, where each dicarboxylic acid may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by one or two xe2x80x94COOZ groups; or Ra is a divalent radical of a phosphorus-containing acid or a divalent silyl radical; or
if m represents 3,
Ra represents a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid, which may be substituted in the aliphatic, cycloaliphatic or aromatic moiety by xe2x80x94COOZ, of an aromatic tricarbamic acid or of a phosphorus-containing acid, or is a trivalent silyl radical; or
if m represents 4,
Ra represents a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetra- carboxylic acid;
if n represents one,
Rb represents C1-C12-alkyl, C5-C7-cycloalkyl, C7-C8-aralkyl, C2-C18-alkanoyl, C3-C5-alkenoyl or benzoyl;
Rc represents C1-C18-alkyl, C5-C7-cycloalkyl, C2-C8-alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, glycidyl or represents a group of the formulae xe2x80x94CH2CH(OH)xe2x80x94Z, xe2x80x94COxe2x80x94Zxe2x80x94 or xe2x80x94CONHxe2x80x94Z wherein Z represents hydrogen, methyl or phenyl, or Rb and Rc together represent the cyclic acyl radical of an aliphatic or aromatic 1,2- or 1,3-dicarboxylic acid;
if n represents two,
Rb is as defined above; and
Rc represents C2-C12-alkylene, C6-C12-arylene, xylylene, a xe2x80x94CH2CH(OH)CH2xe2x80x94Oxe2x80x94Bxe2x80x94Oxe2x80x94CH2CH(OH)CH2xe2x80x94 group, wherein B represents C2-C10-alkylene, C6-C15-arylene or C6-C12-cycloalkylene; or, provided that Rb is not alkanoyl, alkenoyl or benzoyl, Rc represents a divalent acyl radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid or dicarbamic acid, or represents the group xe2x80x94COxe2x80x94; or
Rc represents a group of the partial formula 
wherein T1 and T2 independently of the other represent hydrogen, C1-C18-alkyl, or T1 and T2 together represent C4-C6-alkylene or 3-oxapentamethylene; or
if n represents 3,
Rc represents 2,4,6-triazinyl.
A highly preferred group B0 which contains substituents in 4-position is selected from the group consisting of the partial formulae B1 and B2, wherein
m represents 1;
Ra represents hydrogen, C1-C18-alkyl which is uninterrupted or interrupted by one or more oxygen atoms, 2-cyanoethyl, benzoyl, glycidyl, or represents a monovalent radical of an aliphatic carboxylic acid having 2 to 12 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, of an a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
m represents 2;
Ra represents a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms;
n represents 1;
Rb represents C1-C12-alkyl, C5-C7-cycloalkyl, C7-C8-aralkyl, C2-C8-alkanoyl, C3-C5-alkenoyl or benzoyl; and
Rc represents C1-C18-alkyl, C5-C7-cycloalkyl, C2-C8-alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, glycidyl, or represents a group of the formula xe2x80x94CH2CH(OH)xe2x80x94Z, xe2x80x94COxe2x80x94Z or xe2x80x94CONHxe2x80x94Z, wherein Z is hydrogen, methyl or phenyl.
Another highly preferred group B0 which contains substituents in 4-position is selected from the group consisting of the partial formulae B1 and B2, wherein
m represents 1;
Ra represents hydrogen, C1-C18-alkyl, 2-cyanoethyl, benzoyl, glycidyl, or a monovalent radical of an aliphatic carboxylic acid having 2 to 12 carbon atoms;
m represents 2;
Ra represents a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms;
n represents 1;
Rb represents C1-C12-alkyl, C7-C8-aralkyl, C2-C18-alkanoyl, C3-C5-alkenoyl or benzoyl; and
Rc represents C1-C18-alkyl, glycidyl, a group of the formulae xe2x80x94CH2CH(OH)xe2x80x94Z or xe2x80x94COxe2x80x94Z, wherein Z is hydrogen, methyl or phenyl.
Another particularly preferred embodiment relates to the group B0, wherein one of R9 and R10 represents hydrogen and the other one C1-C4-alkanoylamino.
An especially preferred embodiment of the present invention relates to the process for the preparation of a polymer (IA), wherein
In represents a polymerization initiator fragment of a polymerization initiator capable of initiating polymerization of monomers or oligopolymers containing ethylene groups and which polymerization initiator is selected from the group consisting of C1-C8-alkyl halides, C6-C15-aralkylhalides, C2-C8-haloalkyl esters, arene sulfonyl chlorides, haloalkanenitriles, o-haloacrylates and halolactones;
p represents one;
q represents a numeral from one to three;
A and B represent oligopolymer or polymer fragments containing repeating units of polymerizable monomers selected from the group consisting of styrene, acrolein, acrylonitrile, acrylic or C1-C4-alkylacrylic acid-C1-C4-alkyl esters, acrylic or C1-C4-alkylacrylic hydroxy-C2-C4-alkyl esters, acrylic acid or C1-C4-alkylacrylic di-C1-C4-alkylamino-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylamides and acrylic or C1-C4-alkylacrylic acid anhydrides;
x and y represent numerals greater than one;
R1, R2, R3 and R4 represent methyl;
R5, R6, R7 and R8 represent hydrogen;
the cyclic Nxe2x86x92O fragment in formula IA represents structural embodiments selected from the group consisting of the partial formulae B1 and B2, wherein
m represents 1;
Ra represents hydrogen, C1-C18-alkyl which is uninterrupted or interrupted by one or more oxygen atoms, 2-cyanoethyl, benzoyl, glycidyl, or represents a monovalent radical of an aliphatic carboxylic acid having 2 to 18 carbon atoms, of a cycloaliphatic carboxylic acid having 7 to 15 carbon atoms, or an a,b-unsaturated carboxylic acid having 3 to 5 carbon atoms or of an aromatic carboxylic acid having 7 to 15 carbon atoms;
m represents 2;
Ra represents a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms;
n represents 1;
Rb represents C1-C12-alkyl, C5-C7-cycloalkyl, C7-C8-aralkyl, C2-C18alkanoyl, C3-C5-alkenoyl or benzoyl; and
Rc represents C1-C18-alkyl, C5-C7-cycloalkyl, C2-C8-alkenyl unsubstituted or substituted by a cyano, carbonyl or carbamide group, glycidyl, or represents a group of the formulae xe2x80x94CH2CH(OH)xe2x80x94Z, xe2x80x94COxe2x80x94Z or xe2x80x94CONHxe2x80x94Z wherein Z is hydrogen, methyl or phenyl.
A most preferred embodiment of the present invention relates to the process for the preparation of the polymer (IA), wherein
In represents the polymerization initiator fragment of a polymerization initiator capable of initiating polymerization of monomers or oligopolymers containing ethylene groups and which polymerization initiator is selected from the group consisting of C1-C8-alkylhalides, C6-C15-aralkylhalides, C2-C8-haloalkyl esters, arene sulfonyl chlorides, haloalkanenitriles, xcex1-haloacrylates and halolactones;
p and q represent one;
A and B represent oligopolymer or polymer fragments containing repeating units of polymerizable monomers selected from the group consisting of styrene, acrylic or C1-C4-alkylacrylic acid-C1-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid hydroxy-C2-C4-alkyl esters, acrylic or C1-C4-alkylacrylic acid di-C1-C4-alkylamino-C2-C4-alkyl esters, and acrylic or C1-C4-alkylacrylamides;
x and y represent numerals greater than one;
R1, R2, R3 and R4 represent methyl;
R5, R6, R7 and R8 represent hydrogen;
the cyclic Nxe2x86x92O fragment in formula IA represents structural embodiments selected from the group consisting of the partial formulae B1 and B2, wherein
m represents 1;
Ra represents hydrogen, C1-C18-alkyl, 2-cyanoethyl, benzoyl, glycidyl, a monovalent radical of an aliphatic, carboxylic acid having 2 to 12 carbon atoms;
m represents 2;
Ra represents a divalent radical of an aliphatic dicarboxylic acid having 2 to 36 carbon atoms;
n represents 1;
Rb represents C1-C12-alkyl, C7-C8-aralkyl, C2-C18-alkanoyl, C3-C5-alkenoyl or benzoyl; and
Rc represents C1-C18alkyl, glycidyl, or a group of the formula xe2x80x94CH2CH(OH)xe2x80x94Z or xe2x80x94COxe2x80x94Z, wherein Z is hydrogen, methyl or phenyl.
The (co)polymers (I) as obtained by the process of the present invention typically have a low polydispersity. Preferably the polydispersity is from 1.01 to 2.2, more preferably from 1.01 to 1.9 and most preferably from 1.01 to 1.5.
In the context of the description of the present invention, the term alkyl comprises methyl, ethyl and the isomers of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and dodecyl. An example of aryl-substituted alkyl is benzyl. Examples of alkoxy are methoxy, ethoxy and the isomers of propoxy and butoxy. Examples of alkenyl are vinyl and allyl. An example of alkylene is ethylene, n-propylene or 1,2-propylene.
Some examples of cycloalkyl are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, methylcyclopentyl, dimethylcyclopentyl and methylcyclohexyl. Examples of substituted cycloalkyl are methyl-, dimethyl-, trimethyl-, methoxy-, dimethoxy-, trimethoxy-, trifluoromethyl-, bis-trifluoromethyl- and tris-trifluoromethyl-substituted cyclopentyl and cyclohexyl.
Examples of aryl are phenyl and naphthyl. Examples of aryloxy are phenoxy and naphthyloxy. Examples of substituted aryl are methyl-, dimethyl-, trimethyl-, methoxy-, dimethoxy-, trimethoxy-, trifluoromethyl-, bis-trifluoromethyl- or tris-trifluoromethyl-substituted phenyl. An example of aralkyl is benzyl. Examples of substituted aralkyl are methyl-, dimethyl-, trimethyl-, methoxy-, dimethoxy-, trimethoxy-, trifluoromethyl-, bis-trifluoromethyl or tris-trifluoromethyl-substituted benzyl.
Some examples of an aliphatic carboxylic acid are acetic, propionic or butyric acid. An example of a cycloaliphatic carboxylic acid is cyclohexanoic acid. An example of an aromatic carboxylic acid is benzoic acid. An example of a phosphorus-containing acid is methylphosphonic acid. An example of an aliphatic dicarboxylic acid is malonyl, maleoyl or succinyl. An example of an aromatic dicarboxylic acid is phthaloyl.
The term heterocycloalkyl embraces one or two and heteroaryl from one to four heteroatoms, the heteroatoms being selected from the group consisting of nitrogen, sulfur and oxygen. Some examples of heterocycloalkyl are tetrahydrofuryl, pyrrolidinyl, piperazinyl and tetrahydrothienyl. Some examples of heteroaryl are furyl, thienyl, pyrrolyl, pyridyl and pyrimidinyl.
An example of a monovalent silyl radical is trimethylsilyl.
The process may be carried out in the presence of water or an organic solvent or mixtures thereof. Additional cosolvents or surfactants, such as glycols or ammonium salts of fatty acids, may be added to the reaction mixture. The amount of solvent should be kept as low as possible. The reaction mixture may contain the above-mentioned monomers or oligomers in an amount of 1.0 to 99.9% by weight, preferably 5.0 to 99.9% by weight, and especially preferably 50.0 to 99.9% by weight, based on the monomers present in the polymerizate.
If organic solvents are used, suitable solvents or mixtures of solvents are typically pure alkanes (hexane, heptane, octane, isooctane), hydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons (chlorobenzene), alkanols (methanol, ethanol, ethylene glycol, ethylene glycol monomethyl ether), esters (ethyl acetate, propyl, butyl or hexyl acetate) and ethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether, tetrahydrofurane), or mixtures thereof.
If water is used as a solvent the reaction mixture can be supplemented with a water-miscible or hydrophilic cosolvent. The reaction mixture will then remain in a homogeneous single phase throughout the monomer conversion. Any water-soluble or water-miscible cosolvent may be used, as long as the aqueous solvent medium is effective in providing a solvent system which prevents precipitation or phase separation of the reactants or polymer products until full completion of the polymerization. Exemplary cosolvents useful in the process may be selected from the group consisting of aliphatic alcohols, glycols, ethers, glycol ethers, pyrrolidines, N-alkyl pyrrolidinones, N-alkyl pyrrolidones, polyethylene glycols, polypropylene glycols, amides, carboxylic acids and salts thereof, esters, organosulfides, sulfoxides, sulfones, alcohol derivatives, hydroxyether derivatives such as butyl carbitol or cellosolve, amino alcohols, ketones, and the like, as well as derivatives and mixtures thereof. Specific examples include methanol, ethanol, propanol, dioxane, ethylene glycol, propylene glycol, diethylene glycol, glycerol, dipropylene glycol, tetrahydrofuran, and other water-soluble or water-miscible materials, and mixtures thereof. When mixtures of water and water-soluble or water-miscible organic solvents are selected for the process, the water to cosolvent weight ratio is typically in the range of about 100:0 to about 10:90.
When monomer mixtures or monomer/oligomer mixtures are used, the calculation of mol % is based on an average molecular weight of the mixture.
Hydrophilic monomers, polymers and copolymers of the present invention can be separated from one another or from the polymerization reaction mixture by, for example, distillation, precipitation, extraction, changing the pH of the reaction media or by other well known conventional separation techniques.
The polymerization temperature may range from about 50xc2x0 C. to about 180xc2x0 C., preferably from about 80xc2x0 C. to about 150xc2x0 C. At temperatures above about 180xc2x0 C., the controlled conversion of the monomers into polymers may decrease, and undesirable by-products like thermally initiated polymers are formed or decomposition of the components may occur.
The transition metal in the oxidizable transition metal complex catalyst salt used in the process of the invention is present as an oxidizable complex ion in the lower oxidation state of a redox system. Preferred examples of such redox systems are selected from the group consisting of Group V(B), VI(B), VII(B), VIII, IB and IIB elements, such as Cu+/Cu2+, Cu0/Cu+, Fe0/Fe2+, Fe2+/Fe3+, Cr2+/Cr3+, Co+/Co2+, Co2+/Co3+, Ni0/Ni+, Ni+/Ni2+, Ni2+/Ni3+, Mn0/Mn2+, Mn2+/Mn3+, Mn3+/Mn4+ or Zn+/Zn2+.
The ionic charges are counterbalanced by anionic ligands commonly known in complex chemistry of transition metals, such hydride ions (H+) or anions derived from inorganic or organic acids, examples being halides, e.g. F+, Cl+, Br+or I+, fluoro complexes of the type BF4+, PF6+, SbF6+ or AsF6+, anions of oxygen acids, alcoholates or acetylides or anions of cyclopentadiene.
Anions of oxygen acids are, for example, sulfate, phosphate, perchlorate, perbromate, periodate, antimonate, arsenate, nitrate, carbonate, the anion of a C 1-C8carboxylic acid, such as formate, acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- or trichloro- or -fluoroacetate, sulfonates, for example methylsulfonate, ethylsulfonate, propylsulfonate, butylsulfonate, trifluoromethylsulfonate (triflate), unsubstituted or C1-C4alkyl-, C1-C4alkoxy- or halo-, especially fluoro-, chloro- or bromo-substituted phenylsulfonate or benzylsulfonate, for example tosylate, mesylate, brosylate, p-methoxy- or p-ethoxyphenylsulfonate, pentafluorophenylsulfonate or 2,4,6-triisopropylsulfonate, phosphonates, for example methylphosphonate, ethylphosphonate, propylphosphonate, butylphosphonate, phenylphosphonate, p-methylphenylphosphonate or benzylphosphonate, carboxylates derived from a C1-C8-carboxylic acid, for example formate, acetate, propionate, butyrate, benzoate, phenylacetate, mono-, di- or trichloro- or -fluoroacetate, and also C1-C12-alcoholates, such as straight chain or branched C1-C12-alcoholates, e.g. methanolate or ethanolate.
Anionic ligands and neutral may also be present up to the preferred coordination number of the complex cation, especially four, five or six. Additional negative charges are counterbalanced by cations, especially monovalent cations such as Na+, K+, NH4+ or (C1-C4 alkyl)4N+.
Suitable neutral ligands are inorganic or organic neutral ligands commonly known in complex chemistry of transition metals. They coordinate to the metal ion through a "sgr"-, xcfx80-, xcexc-, xcex7-type bonding or any combinations thereof up to the preferred coordination number of the complex cation. Suitable inorganic ligands are selected from the group consisting of aquo (H2O), amino, nitrogen, carbon monoxide and nitrosyl. Suitable organic ligands are selected from the group consisting of phosphines, e.g. (C6H5)3P, (i-C3H7)3P, (C5H9)3P or (C6H11)3P, di-, tri-, tetra- and hydroxyamines, such as ethylenediamine, ethylenediaminotetraacetate (EDTA), N,N-Dimethyl-Nxe2x80x2,Nxe2x80x2-bis(2-dimethylaminoethyl)-ethylenediamine (Me6TREN), catechol, N, Nxe2x80x2-dimethyl-1,2-benzenediamine, 2-(methylamino)phenol, 3-(methylamino)-2-butanol or N,Nxe2x80x2-bis(1,1-dimethylethyl)-1,2-ethanediamine, N,N,Nxe2x80x2,Nxe2x80x3,Nxe2x80x3-pentamethyldiethyltriamine (PMDETA), C1-C8-glycols or glycerides, e.g. ethylene or propylene glycol or derivatives thereof, e.g. di-, tri- or tetraglyme, and monodentate or bidentate heterocyclic exe2x88x92 donor ligands.
Heterocyclic exe2x88x92 donor ligands are derived, for example, from unsubstituted or substituted heteroarenes from the group consisting of furan, thiophene, pyrrole, pyridine, bis-pyridine, picolylimine, xcex3-pyran, xcex3-thiopyran, phenanthroline, pyrimidine, bis-pyrimidine, pyrazine, indole, coumarone, thionaphthene, carbazole, dibenzofuran, dibenzothiophene, pyrazole, imidazole, benzimidazole, oxazole, thiazole, bis-thiazole, isoxazole, isothiazole, quinoline, bis-quinoline, isoquinoline, bis-isoquinoline, acridine, chromene, phenazine, phenoxazine, phenothiazine, triazine, thianthrene, purine, bis-imidazole and bis-oxazole.
The oxidizable transition metal complex catalyst can be formed in a separate preliminary reaction step from its ligands or is preferably formed in-situ from its transition metal salt, e.g. Cu(I)Cl, which is then converted to the complex compound by addition of compounds corresponding to the ligands present in the complex catalyst, e.g. by addition of ethylenediamine, EDTA, Me6TREN or PMDETA.
After completing the polymerizing step process, the polymers obtained may be isolated or the Nxe2x86x92O compound (IV) is added in-situ. The isolating step of the present process may be carried out by known procedures, e.g. by distilling and filtering off unreacted monomer. After completing the substitution of the polymerisate with the Nxe2x86x92O compound (IV), the catalyst salt is filtered off, followed by evaporation of the solvent or by precipitation of the Nxe2x86x92O polymer (I) in a suitable liquid phase, filtering the precipitated polymer and washing and drying,
The elimination of the leaving group xe2x80x94X and the substitution of the polymerisate with the Nxe2x86x92O (IV) is advantageously performed in such a way that the polymerisate is dissolved in a solvent and the Nxe2x86x92O compound (IV) is added. The reaction takes place within a temperature range from room temperature to the boiling temperature of the reaction mixture, preferably from room temperature to 100xc2x0 C. The transition metal in the oxidizable transition metal complex catalyst salt is converted from its lower oxidation state in the above-mentioned redox systems to its higher oxidation state. In a preferred embodiment of the process a Cu(I) complex catalyst salt is converted to a to the corresponding Cu(II) oxidation state.
Because the present polymerization and derivatization with the Nxe2x86x92O compound (IV) by ATRP is a xe2x80x9clivingxe2x80x9d polymerization, it can be started and terminated practically at will. The various advantages of the process of this type allowing flexible polymerization reactions are described by K. Matyjaszewski in ACS Symp.Ser. Vol. 685 (1998), pg. 2-30. Thus, in one embodiment of this invention, once the first monomer is consumed in the initial polymerizing step, a second monomer can then be added to form a second block on the growing polymer chain in a second polymerization step. Therefore it is possible to carry out additional polymerizations with the same or different monomer(s) to prepare multi-block copolymers. Furthermore, since this is a radical polymerization, blocks can be prepared in essentially any order. One is not necessarily restricted to prepare block copolymers where the sequential polymerizing steps must flow from the least stabilized polymer intermediate to the most stabilized polymer intermediate, such as is the case in ionic polymerization. Thus it is possible to prepare a multi-block copolymer in which a polyacrylonitrile or a poly(meth)acrylate block is prepared first, then a styrene block is attached thereto, and so on.
Furthermore, there is no linking group required for joining the different blocks of the present block copolymer. One can simply add successively monomers to form successive blocks.
The polymers or copolymers can be further processed and used in most cases without any further purification step. This is an important advantage when industrial scale-up is intended.
Another embodiment of the present invention are the polymers, copolymers or oligomers obtainable by the process described above.
Another embodiment of the present invention is a polymer composition which comprises
a) a polymer, copolymer, or oligomer obtainable by the process mentioned above; and
b) a polymer or oligomer of the formula
Axxe2x80x94Byxe2x80x83xe2x80x83(V)
wherein
A represents an oligopolymer or polymer fragment consisting of repeating units of polymerizable monomers or oligopolymers containing ethylene groups;
x represents a numeral greater than one and defines the number of repeating units in A;
B represents a monomer, oligopolymer or polymer fragment copolymerized with A; and
y represents zero or a numeral greater than zero and defines the number of monomer, oligopolymer or polymer repeating units in B.
The polymers obtained by the process of the present invention and the compositions mentioned above may contain in addition to the components mentioned above conventional additives such as antioxidants or light stabilizers may be added in a small quantities, such as UV absorbers, for example those of the hydroxyphenylbenzotriazole, hydroxyphenyl-benzophenone, oxalamide or hydroxyphenyl-s-triazine type. These compounds can be added individually or in mixtures, with or without sterically hindered amines (HALS).
The composition may contain the above-mentioned polymer or oligomer components in an amount of 0.01 to 99% by weight, preferably 0.1 to 95% by weight, particularly preferably 1 to 90% by weight, and especially preferably 5 to 80% by weight, based on the monomers present in the composition.
The polymers obtained by the process of the present invention and the compositions mentioned above are useful as adhesives, detergents, dispersants, emulsifiers, surfactants, defoamers, adhesion promoters, corrosion inhibitors, viscosity improvers, lubricants, rheology modifiers, thickeners, crosslinkers, paper treatment compositions, water treatment compositions, electronic materials, paints, coatings, ink materials, imaging materials, superabsorbants, cosmetics, hair products, preservatives, biocide materials or modifiers for asphalt, leather, textiles, ceramics and wood.
Nxe2x86x92O compounds of the formula IV are known. They are commercially available or can be prepared according to the methods as described in U.S. Pat. No. 5,204,473 or U.S. Pat. No. 4,581,429 and the references cited therein.